IMMUNOASSAY OF INSULIN WITH INSULIN-ANTIBODY PRECIPITATE
IMMUNOASSAY OF INSULIN WITH INSULIN-ANTIBODY PRECIPITATE
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DOI：
10.1042/bj0880137
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发表时间：
1963-01-01
影响因子：
4.1
通讯作者：
RANDLE, PJ
中科院分区：
文献类型：
--
作者：
HALES, CN;RANDLE, PJ
本文介绍了用豚鼠抗人胰岛素血清、碘131标记牛胰岛素和兔抗丙种球蛋白血清测定胰岛素的三种新方法。在方法A中，使用抗胰岛素血清从含有固定量的1131标记胰岛素的溶液中获得胰岛素样品，所述1131标记胰岛素与用抗γ球蛋白血清沉淀的标准或未知溶液混合，并通过过滤分离沉淀物。沉淀物中放射性的测定允许通过参考标准曲线测定胰岛素。在方法B中，首先用抗γ-球蛋白血清沉淀胰岛素抗体，并将沉淀物用于对胰岛素混合物进行取样。方法C是方法B的改进，其中通过在引入I 131标记的胰岛素之前将沉淀的胰岛素抗体与未标记的胰岛素孵育来实现更高的灵敏度。如果抗丙种球蛋白血清不过量，则血浆丙种球蛋白可干扰方法A，但不会干扰方法B或C。因此，后者优选用于测定血浆中的胰岛素。方法A和B原则上基于同位素稀释，但实际上不遵守该原则，因为抗体结合的胰岛素量随胰岛素浓度而变化。用比活度为5-20 mc/mg的1131标记胰岛素，用这些方法可以检测到6 x 10-6 iu（6微单位）人胰岛素/ml。5名正常人空腹后、口服葡萄糖（50或100 g）后16、30、60和150 min血浆胰岛素浓度分别为64和158、65和49、22和21 μ U/ml。
Three new methods for immunoassay of insulin with guinea-pig anti-(human insulin) serum, I131-labelled ox insulin and rabbit anti-gamma-globulin serum are described. In method A anti-insulin serum is used to obtain samples of insulin from solutions containing a fixed amount of 1131-labelled insulin mixed with standard or unknown solutions being precipitated with anti-gamma-globulin serum and the precipitate separated by filtration. Assay of radioactivity in the precipitate then permits the determination of insulin by reference to a standard curve. In method B insulin antibody is first precipitated with anti-gamma-globulin serum and the precipitate used to sample insulin mixtures. Method C is a modification of method B in which greater sensitivity is achieved by incubating the precipitated insulin antibody with unlabelled insulin before introducing the I131-labelled insulin. Plasma gamma-globulin can interfere in method A if anti-gamma-globulin serum is not in excess but it cannot interfere in methods B or C. The latter are therefore preferred for the assay of insulin in blood plasma. Methods A and B are in principle based on isotope dilution, but in practice this principle is not obeyed because the amount of insulin bound by antibody varies with the insulin concentration. With 1131-labelled insulin of specific activity 5-20 mc/mg, 6 x 10-6 iu (6 microunits) of human insulin/ml can be detected with these methods. The plasma insulin concentration in 5 normal people was (in microunits/ml) after starvation, 16; and 30, 60 and 150 min. after the oral administration of glucose (50 or 100 g), 64 and 158, 65 and 49, and 22 and 21 respectively.